This invention relates to windshield wiping apparatus and particularly to squeegees (wiping elements) used in conjunction therewith.
Windshield wiper squeegees customarily are composed of an elastomeric molded or extruded element having a retention bead, for engagement with the remainder of the windshield wiper, joined to an elongated wiping portion through a reduced neck. The wiping portion is customarily provided with a series of stair-stepped wiping surfaces along its shank which, upon lay-over of the squeegee during wiping, supposedly assist the terminal wiping lip in the wiping function. Other types of squeegees have either curved or substantially straight shank portions, however, these shank portions have generally not been designed to withstand ozone attack particularly at stress concentration portions along the shank. It has been found that ozone in the atmosphere attacks the areas which are under maximum stress concentration, creating cracks in the squeegee which lead to premature failure of the wiping member. To compensate for this problem, many wiping elements employ overly thickened cross sections which may retard the failure problem, at the expense of increased materials cost.
It is the primary object of this invention to produce a wiping element which has a shank portion designed to minimize, if not eliminate, stress concentration areas for increased life and resistance to chemical attack, while simultaneously using a minimum of material to achieve the correct wiping angle during operation.